Hiya.
Unfortunately, there are no chew toys or hard foods that will solve this problem since it is primarily the wearing the teeth (incisors *and* molars) against each other during chewing that keeps them at their normal length and shape.
It Should not be a problem for him to be anesthetized as the majority of rabbits with molar spurs have it when they reach a more mature age, So your vet should be experienced in dealing with this.
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